BRODIE ABSCESS - MR-IMAGING APPEARANCE IN 10 PATIENTS

The magnetic resonance (MR) imaging features of Brodie abscess have no t yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bon e abscess had a characteristic ''target'' appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time invers ion recovery) images, (b) an inner ring isointense to muscle on T1-wei ghted images and with high signal intensity on T2-weighted and STIR im ages, (c) an outer ring hypointense on all images, and (d) a periphera l halo hypointense on TI-weighted images. In six of eight cases, a sof t-tissue mass was found. The two vertebral abscesses had a less specif ic appearance, with low signal intensity on T1-weighted images and hig h signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.